Apr 122017

Perhaps your grandmother had Alzheimer’s disease; maybe your mom or dad is currently living with the disease. You may be concerned that you are seeing signs of the disease in yourself or a loved one. Whatever the situation, if your family has been touched by Alzheimer’s, it is natural to be curious if a genetic test is valuable in predicting the likelihood of developing the disease. Although the cause of Alzheimer’s is still unknown, scientists have identified a number of genes that impact your risk of developing the disease.

On Thursday, April 6, the U.S. Food and Drug Administration (FDA) announced that they have approved at-home genetic testing through the 23andMe Personal Genome Service Genetic Health Risk (GHR) test, which tests for genes associated with risk of 10 diseases or conditions, including late-onset Alzheimer’s. People will be able to send 23andMe a saliva sample and receive their genetic data back through the mail.

We spoke with Keith Fargo, Ph.D., Director of Scientific Programs and Outreach at the Alzheimer’s Association, about what you need to know about this type of testing – and what the results tell (and don’t tell) you.

Two categories of genes influence whether a person develops a disease: risk genes and deterministic genes. Alzheimer’s genes have been found in both categories. Can you explain the difference between these types of genes?

Risk genes increase the likelihood of developing a disease, but do not guarantee it will happen. Deterministic genes directly cause a disease; they guarantee that anyone who inherits one will develop the disorder.

23andMe says their genetic test evaluates more than 500,000 genes and gene variants. Regarding Alzheimer’s, it evaluates whether you have the APOE-e4 Alzheimer’s risk gene. It was the first Alzheimer’s risk gene identified and remains the one with strongest impact. Having one copy of the APOE-e4 gene increases your risk – having two copies increases it more – but it is hard to say exactly how much for any individual.

There are two other variations of APOE, known as e2 and e3. The e3 variation is relatively neutral and the e2 variation may provide some protection against Alzheimer’s dementia. The newly approved test does not evaluate for these variants. Plus, there are nearly 30 other genes that have been identified to also affect risk of late-onset Alzheimer’s, but (a) those genes don’t impact risk as much as APOE-e4, and (b) this test does not evaluate for them.

There are three more genes that have misspelling in their DNA or mutations where, if you have one, it’s a virtual certainty that you will develop Alzheimer’s dementia. These are the deterministic genes. The 23andMe test does not look for these gene mutations, either.

Part of the challenge with understanding the value of the newly approved test is that many people who have APOE-e4 never experience Alzheimer’s dementia symptoms, and many who do develop the disease do not have any copies of APOE-e4.

For this reason, and because of the current lack of proven preventive strategies, the Alzheimer’s Association does not recommend genetic testing for Alzheimer’s disease for the general population. If you are concerned about Alzheimer’s disease or memory changes in yourself or a loved one, the Association encourages you to have a frank conversation about your risk with your healthcare provider.

If someone’s parent or sibling had or has Alzheimer’s, is he or she at a higher risk of developing the disease?

The fact is this: everyone is already at risk. Of people 85 and older, one third of them have Alzheimer’s dementia. And having a family history of Alzheimer’s is not necessary for someone to develop the disease.

That being said, people who have a parent, brother or sister with Alzheimer’s are more likely to develop the disease, and those who have more than one first-degree relative with the disease are at even higher risk. But, again, it is hard to say exactly how much an individual’s risk may be.

If someone is interested in having genetic testing done, what are the first steps he or she should take?

The Alzheimer’s Association suggests that you talk to a genetic counselor before deciding to take the test and, if you decide to get genetic testing for Alzheimer’s, again after you receive the results. The National Society of Genetic Counselors website provides a searchable directory to locate a counselor by location and specialty.

What are the benefits of speaking with a genetic counselor?

A genetic counselor can help you understand what the test does and does not do. He or she can help you work through making a decision that is best for you in terms of ordering the genetic testing kit. Once you get the results back, he or she can help you determine what the results really mean.

Some people think that this is a diagnostic test for Alzheimer’s, but it’s not. It is a test for the presence of one or two copies of the APOE-e4 Alzheimer’s risk gene. It’s not going to answer the question most people have, which is: “Will I get Alzheimer’s disease?” You can have two copies of APOE-e4 and never develop Alzheimer’s disease. Conversely, you can have no copies of the gene and still develop the disease.

Do you believe that taking a genetic test is a proactive step in controlling one’s health?

For some people, yes. It may give them the motivation they need to make lifestyle changes that can reduce their risk of cognitive decline as they age, and possibly even reduce their risk of dementia. In fact, there are behaviors that we should all be doing to keep our brain healthy as we age. As a starting point, the Alzheimer’s Association has research-based brain health tips that we call 10 Ways to Love Your Brain. You can find them at www.alz.org.

That said, at the Alzheimer’s Association, we are concerned that people who receive results that confirm they don’t carry APOE-e4 will assume that means they won’t develop Alzheimer’s. The truth is that these people are still at risk.

With an unsupervised at-home test, there is a real possibility of people misunderstanding their results, which could result in making misinformed decisions about their health. A genetic counselor can be helpful in making informed decisions. If you choose to take a genetic test, discuss it with a genetic counselor before and after so that you are educated about the process, the test and what the results mean. And if you are already experiencing symptoms of cognitive decline, see a healthcare professional for a full evaluation.

Learn more:


  9 Responses to “FDA Approves At-Home Test for an Alzheimer’s Disease Risk Gene: What You Need to Know”

  1. I am a lonely eighty three year old woman caring for my husband who is eighty six years old. It is a 24/7/365 days job and I have no help. I have two children who only criticise and make my life more difficult-but do not do a thing to help the father. My daughter brings him food occasionally which he enjoys while my son lives in US and so cannot help. They do not understand what it is to give constant care to a dementia patient and not have anyone close to you to confide and receive their empathy-I do not want their sympathy but miss having someone to open up to.

    All that my children do is to denigrate me and make me feel I am not doing the right thing when I am trying so hard to do my best. My husband functions better if he is encouraged to do things and be treated near normal as possible which he is. I do not believe in pushing him into dementia but having been married to him for 57 years know his personality needs to be encouraged to be independent and feel he is the man he was . Am I wrong?

    • Hello S. Melder-

      We are sorry to hear about what you are going through. Please call us at 800.272.3900 at any time, 24/7. We are here to help.

    • I’m so sorry to hear that your children aren’t supporting you. My mother is in the late stage of Alzheimer’s and is 86 yrs old. My sister cares for her in mother’s home. It’s a full time job! She has support from me and my other sisters, so we are very fortunate. It takes all of us though to care for Mother. I hope your children will realize that you need help and agree to help you more. You might consider sending your note to them. Sometimes children don’t realize how much they are needed. Communication is very important, and it’s not easy to talk about our health problems with each other. Also, call the Alzheimer’s hotline number and your any friends you might have. There are many volunteer resources and home health agencies that can help too in most communities. Alzheimer’s can help you find this kind of help. Don’t forget to take care of yourself too! God bless you and your husband! ~ Erica Khorsandi

  2. This doesn't sound like a conclusive test to me. If it's not taking all genetic factors into consideration and only looks at one, why bother? Pass on this test.

    • I agree Kathleen. Why waste precious time and money on a test that doesn’t really give you conclusive HOPE?????????? Common sense people. These are people. No.

    • I agree Kathleen. Just a waste of time and money. Not much hope with that one.

  3. Would an Alzheimer's / general dementia expert please answer this question:
    When we read articles like this that contain information about Alzheimer's, can this information usually be generalized to include all forms of dementia – and if not, how do we know when it does or does not pertain to all forms?
    Thank you very much!

  4. I am having memory problems and while if I write things I'm doing okay. Whenever my GP wants to see me after a tests he insists that I bring a friend (which is referred to a "tag-a-long" It is NOT conclusive about my memory problems, I have been no harm to myself or others i just am concerned about it and am following thru with tests (CAT – MRI) Yet I feel this reference to a "tag-a-long" is not helpful to the process of pinning this memory problem….how about bring along a "friend."?

  5. I think the topic of whether or not the results of these tests are kept confidential should be discussed in an article like this. I understand that there are still loopholes to these tests which may leave the client vulnerable to the information from these tests getting to insurance companies, the government, etc.

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